Shake, Rattle and Roll

Type of Lesson: Experiment and discussion

Time Needed: 20-30 minutes

National Standards Addressed

Earth and Space Science, Grades K-4: Earth materials are solid rocks and soils, water, and the gases of the atmosphere. The varied materials have different physical and chemical properties, which make them useful in different ways, for example, as building materials, as sources of fuel, or for growing the plants we use as food. Earth materials provide many of the resources that humans use.

Earth and Space Science, Grades K-4: The surface of the earth changes. Some changes are due to slow processes, such as erosion and weathering, and some changes are due to rapid processes, such as landslides, volcanic eruptions, and earthquakes.

Earth and Space Science, Grades 5-8: Some changes in the solid earth can be described as the “rock cycle.” Old rocks at the earth’s surface weather, forming sediments that are buried, then compacted, heated, and often recrystallized into new rock. Eventually, those new rocks may be brought to the surface by the forces that drive plate motions, and the rock cycle continues.

Earth and Space Science, Grades 9-12: Interactions among the solid earth, the oceans, the atmosphere and organisms have resulted in the ongoing evolution of the earth system. We can observe some changes such as earthquakes and volcanic eruptions on a human time scale, but many processes such as mountain building and plate movements take place over hundreds of millions of years.

Physical Science, Grades K-4: Objects have many observable properties, including size, weight, shape, color, temperature, and the ability to react with other substances. Those properties can be measured using tools, such as rulers, balances, and thermometers.

Physical Science, Grades 5-8: A substance has characteristic properties, such as density, a boiling point, and solubility, all of which are independent of the amount of the sample. A mixture of substances often can be separated into the original substances using one or more of the characteristic properties.

Quick Summary of Lesson

This experiment will guide students in quantitatively comparing the weathering of different-sized materials.

Materials

Two sizes of salt pellets ( Morton's Water Softner Salt) for class comparison (half of the groups in your class will need 100 grams of whole salt pellets and the other half of the groups will need 100 grams of broken salt pellets)
tennis ball container with lid (1/group)
clock with second timer (1/group)
graduated cylinder (1/group)
100 mL of room temperature water (1/group)
balance (digital would work best) (1 or 2 for class)
sink or empty container in which to dump water (1 or 2 for class)
student worksheet available in Student Activity Sheet section below (1/student)

Procedure

1. Each group of 4 students should obtain a weighed sample of salt (as close to 100 grams as possible). Half of the groups should get 100 grams of whole salt pellets and half of the groups should get 100 grams of broken pellets. Each group should place their salt in their tennis ball container. The group should record whether they have whole salt pellets or broken salt pellets in the first column of the table on the Student Activity Sheet.
2. Record the weight of the salt sample plus the tennis ball container on the worksheet in the Dry Weight column.
3. Add 100 mL of water to the weighed container. Place the lid on the container and shake the tennis ball container at a steady rate for 1 minute (each student should shake for about 15 seconds).
4. Open the container and decant (pour off) the water.
5. Record the "wet weight" of the wet salt pellets plus the tennis ball container. Place this value on the worksheet under Wet Weight.
6. Be sure to copy the results that other groups got from the board or overhead into the remaining rows of your worksheet table.
7. Answer all the questions on the worksheet.

Student Activity Sheet

Please click here for student activity sheets. All activities on the Windows to the Universe site may be printed and reproduced if being used for educational purposes.

Notes to the Teacher

The purpose of the lab is to compare the weathering of different-sized materials. The class will work in groups of 4. Each group will be responsible for performing the procedures for either whole salt pellets or broken salt pellets. The group must then share their results with the rest of the class as well as get other results so that a comparison can be made. Reproduce table on Student Activity Sheet by drawing it on the board or by making an overhead of the table.

Rocks and minerals undergo physical and chemical weathering. One type of weathering that rocks and minerals undergo is when water dissolves the minerals. Some minerals are more resistant to weathering than others. For instance, quartz is a very resistant mineral.

Surface area also affects weathering; the more surface area exposed, the more weathering that will take place. As results should show, the smaller the pieces of salt, the more that gets dissolved!

Weathering is the wearing away of material (happens in place) and erosion involves the removal and transport of material (movement). The USGS has a good page that further describes the difference.